CRAZY ABOUT COMETS

The ancient Chinese thought they were celestial brooms wielded by the gods to sweep the heavens free of evil. In the West they were believed to presage the fall of Jerusalem, the death of monarchs and such anomalies as two-headed calves. The Norman Conquest of England was attributed to the 1066 flyby of Halley's, history's most famous comet, which has been linked to everything from Julius Caesar's assassination to the defeat of Attila the Hun. Told that Earth would pass through Halley's tail during its 1910 visit, many Americans panicked and bought gas masks and "comet pills."